Imagine sitting at 35,000 feet, sipping a drink, when you look out the window and see a gray military fighter jet tracking your exact speed just yards away. That is exactly what happened on June 30, 2026, to 180 passengers flying from Warsaw to Tel Aviv.
A routine summer flight turned into an international security incident because of a digital glitch. Code 7500 flashed across European radar screens. In aviation, that code means only one thing: unlawful interference. A hijacking.
What followed was a tense, multi-nation scramble involving NATO, Bulgarian MiG-29s, Turkish F-16s, and Israeli interceptors. It reveals how terrifyingly fast the modern aviation security apparatus reacts when a system errors out.
The Anatomy of Flight 155
The flight was LOT Polish Airlines Flight 155. It wasn't actually flying on a Polish plane, though. It was a wet-lease arrangement using an Airbus A320 operated by Bulgaria-based Electra Airways. This is standard industry practice, but it added layers of bureaucracy when things went south.
The plane left Warsaw on Tuesday morning. Everything seemed fine until it hit Bulgarian airspace. Suddenly, the aircraft transponder started broadcasting squawk code 7500.
Air traffic controllers don't guess when they see 7500. They assume the worst. The transponder is the primary way a plane tells the ground what is happening. If it says there is a hijacking, the system believes it.
NATO's Combined Air Operations Centre in Torrejón, Spain, immediately flagged the flight. They sent an alert to the Bulgarian military. At 1:54 p.m. local time, a Bulgarian MiG-29 roared off the runway at Graf Ignatievo Air Base. Within three minutes, it intercepted the Airbus near the Danube border.
The Domino Effect Over the Mediterranean
The Bulgarian pilot did standard visual checks and established contact. The crew inside the Airbus insisted everything was completely normal. But when a transponder screams hijacking, you can't just take someone's word for it over the radio. A hijacker could be holding a knife to the pilot's throat, forcing them to speak calmly.
The plane moved out of Bulgaria and entered Turkish airspace. The Bulgarians handed off the watch to Turkey. Ankara did not hesitate. They scrambled two F-16 fighter jets to shadow the plane.
By the time the flight neared Cyprus and the Eastern Mediterranean, Israel entered the picture. The Israel Defense Forces scrambled their own fighter jets.
The security apparatus in the Middle East is on permanent high alert. A passenger plane broadcasting a hijack code moving toward Tel Aviv is a worst-case scenario.
Then came the logistical nightmare. The flight crew wanted to land. They tried to get clearance in Cyprus at Paphos Airport. Denied. They tried to continue to Israel. Denied. Turkey wouldn't let them land either.
When a plane is suspected of being a weaponized flying bomb or a hostage situation, nobody wants it on their tarmac.
Squawk 7500 and the Danger of Silent Alerts
To understand why everyone panicked, you need to know how transponders work. Pilots use four-digit codes called "squawk codes" to communicate basic status information to air traffic control.
Most codes are just random numbers assigned by controllers to keep track of who is who. But a few codes are universally reserved for emergencies.
- 7500: Hijacking / Unlawful Interference
- 7600: Radio Failure / Lost Communications
- 7700: General Emergency
Code 7500 is unique because it is designed to be entered silently. If terrorists take over a cockpit, the pilot can quietly turn the dial to 7500 without saying a word. The moment that code hits the radar screen, it triggers a quiet alarm on the ground.
Because it is meant to be a secret cry for help, a subsequent radio message saying "everything is fine" is treated with extreme skepticism. Security protocols require visual confirmation from fighter pilots and often require the plane to land at a designated, secure airport where special forces can storm the aircraft.
Blame Game Between Human Error and Broken Tech
As soon as Flight 155 landed safely, the finger-pointing started. Early statements from airport officials and Turkish authorities blamed pilot error. They claimed a pilot simply fat-fingered the dial, accidentally setting the transponder to 7500 instead of a standard transit code.
LOT Polish Airlines spokesman Krzysztof Moczulski initially indicated to Polish state media that it looked like human error. It wouldn't be the first time. Pilots switching codes can occasionally overshoot a number or punch in the wrong digits.
Bulgaria's Ministry of Transport pushed back with a different explanation. They released an official statement asserting that a technical malfunction inside the transponder unit itself caused the chaos. According to the ministry, a hardware glitch caused the machine to broadcast the hijack signal on its own, completely independent of whatever the pilots were doing in the cockpit.
The alarm actually triggered twice. It fired off once when entering Bulgarian space, and then again after leaving Turkish space. That repetitive behavior supports the broken hardware theory. A pilot might make a mistake once, but they rarely make the exact same catastrophic mistake twice in an hour.
The Exhaustion Redirection to Burgas
After being rejected by Israel, Cyprus, and Turkey, the crew faced a critical problem. They were running out of time. Not just fuel time, but legal working hours.
Aviation laws strictly limit how long a flight crew can stay on duty. The stress of being shadowed by three different air forces while circling over the Mediterranean burned through their clock.
The operator requested a diversion back to Bulgaria. Since Electra Airways is based at Burgas Airport on the Black Sea coast, that was the logical choice. The Bulgarian military scrambled jets for a second time to escort the plane back to their territory.
At 5:12 p.m., the Airbus finally touched down in Burgas.
The ordeal wasn't over for the 180 passengers. The plane was immediately isolated on a remote taxiway, far away from terminal buildings and other aircraft. Bulgarian police and counter-terrorism units surrounded the jet. Passengers were taken off the plane under armed guard and forced through intense security screenings to verify that no hijackers were hiding among them.
Once the authorities verified the cockpit was clean and the passengers were safe, the plane was cleared. The broken transponder was fixed or replaced, and the flight finally departed Burgas late that night around 11:00 p.m.
The Growing Risk of Avionics Vulnerabilities
This incident highlights a major vulnerability in modern aviation. We rely entirely on digital signals to determine if a multi-million dollar aircraft is safe or a threat.
When those systems glitch, the response is massive, expensive, and dangerous. Scrambling fighter jets costs thousands of dollars per hour. Forcing a commercial airliner to circle frantically over the sea increases the risk of fuel starvation or pilot disorientation.
Aviation experts are increasingly worried about the reliability of aging avionics. Transponders are robust systems, but they can suffer from electrical shorts, moisture damage, or software bugs.
If a simple hardware failure can trick NATO and multiple national militaries into preparing for a counter-terrorism operation, the system needs better verification checks.
Relying solely on a four-digit squawk code without a secondary, unhackable verification method creates a single point of failure.
If you are a frequent flyer, don't panic. These events are incredibly rare. Airlines inspect these systems thoroughly before flight. But when a glitch does slip through, the military response will always be swift and uncompromising. They will always choose to scramble jets and ask questions later.
If you ever see a fighter jet outside your cabin window, check the flight tracker. Your plane's electronics might just be having a very bad day. Check your airline’s policy on wet-leased flights if you want to know exactly who is operating your next journey. Knowing the actual carrier can give you a better idea of their maintenance hubs if an emergency redirection happens.
